JPS5920337A - Stabilized polyolefin resin composition - Google Patents

Abstract

PURPOSE:To provide the titled resin compsn. having excellent resistance to heat and oxidation, containing tetrakis[methylene-3-(3-methyl-5-t-butyl-4-hydroxyphenyl) propionate]methane and pentaerythritol tetrakis (beta-alkyl thiopropionate). CONSTITUTION:A polyolefin resin compsn. contains tetrakis[methylene-3-(3- methyl-5-t-butyl-4-hydroxyphenyl) propionate]methane and pentaerythritol tetrakis (beta-alkyl thiopropionate) of the formula (wherein R is a 4-20C alkyl) in a weight ratio of 1:0.5-15. As the polyolefin resin to be stabilized, polypropylene is particularly preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyolefin resin compositions having excellent thermal and oxidative stability.

Polyolefin resins have excellent physical, chemical, and electrical properties, so they can be processed into molded products, pipes, sheets, films, etc. by various methods such as blow molding, extrusion molding, injection molding, or calendering. , used in many fields. When polyolefin resins such as polyethylene and polypropylene are used alone, they will deteriorate due to the action of heat and oxygen during processing or use, and their physical properties will deteriorate significantly with phenomena such as softening, embrittlement, and discoloration. well known. In order to prevent such a phenomenon, various phenol-based, phosphorus-based, sulfur-based, and other antioxidants have been added singly or in combination during the production and processing steps of polyolefin resins.

For example, 2,6-di[-butyl-4-methylphenol, n-octadecyl-β-(3°5-di-t-7'thyl-4-hydroxyphenyl)propionate, tetrakis[methylene-3-(3 ,5-di-t-butyl-4-
hydroxyphenyl)-flobionate comethane, 3.
5-trimethyl-2,4,6-1-lis(3,5-di-1
-butyl-4-hydroxybenzyl)benzene, 1,1
．． 3-tris(2-methyl-4-hydroxy-5-1-
butylphenyl) phthane or these antioxidants and dilaurylthiodipropionate, simiristylthiodipropionate, distearylthiodipropionate or pentaerythritol-tetrakis (β-dodecylthiodipropionate). Methods such as combination with propionate) are known. However, these methods are still not fully satisfactory in terms of thermal and oxidative stability.

As a result of various studies to solve these problems, the present inventors have found that by blending a specific phenol compound and a specific sulfur compound into a polyolefin resin, the present inventors can overcome the conventional combination technology of antioxidants. We have discovered that a surprising synergistic effect can be obtained that is completely unpredictable.
Furthermore, surprisingly, it was found that it has extremely superior thermal and oxidative stability compared to the prior art, leading to the present invention.

That is, the present invention provides tetrakis[methylene-3-(3
-methyl-5-1-butyl-4-hydroxyphenyl)
Propionate comethane [Compound I] and pentaerythritol-tetrakis (β-alkylthiopropionate) represented by the general formula % formula % (in the formula, K represents an alkyl group having 4 to 20 carbon atoms) [Compound ■] I:■71
:0.5 to 15 (weight ratio).

Tetrakis [methylene-3-(3-
Methyl-5-tert-butyl-4-hydroxyphenyl)propionate comethane is a combination of pentaerythritol and 3-
(3-Methyl-5-tert-butyl-4-hydroxyphenyl)furopionic acid, prepared by conventional esterification reactions with its acid halides, acid anhydrides or mixed acid anhydrides; It can be produced by a conventional transesterification reaction with a lower alkyl ester.

Note that tetrakis [methylene-3-(
3-Methyl-5-butyl-4-hydroxyphenyl propionate As a phenolic compound similar to comethane, a 3.5-dialkyl-4-hydroxyphenyl group skeleton compound is described in Japanese Patent Publication No. 42-9651. However, in such phenolic compounds, the two alkyl groups at the ○-position of the hydroxyl group are based on the concept of a [-butyl group, that is, a sterically hindered dialkyl-substituted phenol derivative, and a specific compound is tetrakis[methylene-3]. -(3°5-dit-"ifyl--hydroxyphenyl)propionate comethane is described.

However, the compound (I) used in the present invention is a dialkyl-substituted phenol derivative in which one of the two alkyl groups at the ○-position of the hydroxyl group is a methyl group without steric hindrance. It is distinguished from the group of dialkyl-substituted phenol derivatives described in patent literature.

In pentaerythritol-tetrakis (β-alkylthiopropionate) represented by the above general formula, which is another component used in the present invention, the substituent has 4 carbon atoms.
-20 alkyl groups, but from the viewpoint of thermal and oxidative stability, alkyl groups having 6 to 18 carbon atoms are preferred, and alkyl groups having 12 carbon atoms are most preferred. An example of a compound that can be oxidized is pentaerythritol-tetrakis (β-
hexylthiopropionate), pentaerythritol-tetrakis (β-dodecylthiopropionate), and pentaerythritol-tetrakis (β-octadecylthiopropionate).

In the polyolefin resin composition of the present invention, the compound (1
) and compound (II) in the polyolefin resin 1
The amount is usually 0.01 to 5 parts by weight, preferably 0.05 to 1 part by weight.

The weight ratio of compound (II) to compound (I) is 0.5 to 15, preferably 1 to 10, more preferably 2 to 6.

Here, if the compound fn) is less than 0.5 times the weight of the compound TI), it is difficult to obtain the desired effect sufficiently, and even if the compound (■) exceeds 15 times the weight, the corresponding effect cannot be obtained. difficult and economically disadvantageous.

In the present invention, in order to blend the compound fI) and the compound (III) into the polyolefin resin, the known equipment and operation methods for blending stabilizers, pigments, fillers, etc. into the polyolefin resin can be applied almost as they are.

The polyolefin resin composition of the present invention may contain other additives, such as ultraviolet absorbers, light stabilizers, antioxidants, metal deactivators, metal soaps, nucleating agents, lubricants, antistatic agents, and flame release agents. , pigments and fillers.

In particular, ultraviolet absorbers, hindered amine light stabilizers, etc., such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2(2'-1=droxy-5'-methylphenyl)benzo triazole, 2(2'-hydroxy-3'-
t-Butyl-5'-7'f-ruphenyl)-5-chloro-
Benzotriazole, 2(2-hydroxy-3',5'
-di-t=buphenyl)-5-10-lowbenzotriazole, 2(2'-hydroxy-3',5'-di-amylphenyl)benzotriazole, [2,2'-thiobis(4-[-octyl Phenol-1.)]-butylamine Ni salt, 2, 2.5゜6-tetramethyl-4-piperidinyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 2 −(3,
5-di[-butyl-4-hydroxybenzyl)-2-
n-butyl-malonate bis(1,2,2゜6.6-pentamethyl-4-piperidyl), 1-(2-(3-(3,
5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl) -4-(3-(3,5-di-
t-Butyl-4-hydroxyphenyl)propionyloxy)-2,2,6,6-titramethylpiperidine, dimethyl succinate 1-(2-hydroxyethyl)-4-
The light resistance can be improved by adding hydroxy-2,2,6,6-titramethylpiperidine polycondensate or the like.

Further, by adding other phosphite-based antioxidants to the composition of the present invention, the hue can be improved. These phosphite antioxidants include:
For example, distearyl pentaerythritol diphosphite, tris(2,4-di-L-butylphenyl) phosphite, l.lis(2-1-butyl-4-methylphenyl) phosphite, bis(2,4-di[ -butylphenyl)pentaerythritol diphosphite, tetrakis(2,4-di[-butylphenyl)-4,4'-
Examples include biphenylene diphosphite.

Polyolefin resins stabilized by the present invention include low-density polyethylene, medium-high density polyethylene, linear low-density polyethylene, polypropylene, polybutene-
Polyα-olefins such as 1, propylene-ethylene random or block copolymers, ethylene-butene-1
Poly α-olefin copolymers such as random copolymers,
Among these, it is particularly effective for polypropylene modified with maleic anhydride.

EXAMPLES Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 After mixing the following formulation with a mixer for 5 minutes, the mixture was heated to 180°C.
The compound obtained by melting and kneading with a mixing roll was formed into a sheet with a thickness of 1 mm using a hot press at 210°C, and a test piece of 40 x 40 x 1 rqm was prepared. The time required for 30% of the specimen area to become embrittled in a gear oven at 160°C was measured, and this time was taken as the thermal embrittlement induction period to evaluate thermal and oxidative stability. The results are shown in Table-1.

<Blend> Unstabilized polypropylene resin 100 parts by weight Calcium stearate O01 test compound
Variables In Table 11, the symbols for test compounds indicate the following compounds.

■ Tetrakis [methylene-3-(3-methyl-5
-t-Butyl-4-hydroxyphenyl)propionate comethane n-1 Pentaerythritol-tetrakis (β-bexylthiopropionate) II-2 Pentaerythritol-tetrakis (β-dodecylthiopropionate) II-3 Pentaerythritol-tetrakis (β-octadecylthiopropionate) AO-1n-octadecyl-β-(3,5-di[-butyl-4-hydroxyphenyl)propionate AO-2tetrakis [methylene-3-(3゜5-G-t
-Butyl-4-hydroxyphenyl)propionate comethane AO-31,3,5-)listyl-2,4°6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene AO- 41,1,3-)Lis(2-methyl-4-hydroxy-5t-butylphenyl)butane AO-5 dilaurylthiodipropionate AO-6 distearylthiodipionate procedural amendment (voluntary) 1981 Kazuo Wakasugi, Commissioner of the Japan Patent Office, September 1998, 1982, Patent Application No. 180684, 2 Name of the invention, Stabilized Polyolefin Resin Composition 3, Relationship with the Amendment Case, Patent Applicant Residence Address: 5-5 Kitahama, Higashi-ku, Osaka Name (209)
) Sumitomo Chemical Co., Ltd. Representative Hijikata
Take 4, Agent address: 5-5 Kitahama, Higashi-ku, Osaka Detailed description of the invention in the specification column 6 Contents of amendment (1) Mei 114E, page 8, line 10, l'l, 5
-J is corrected to l'-1, 8, 5-J.

(2) On page 7, lines 8 to 2 from the bottom, it says, ``It will be disadvantageous.

” is disadvantageous to U. Correct it.

that's all

Claims (1)

[Scope of Claims] (1) Tetrakis [methylene-3-(3-methyl-
5-t-butyl-4-hydroxyphenyl) propionate comethane and pentaerythritol-tetrakis (β-alkylthiopropyl) represented by the general formula % formula % (wherein k represents an alkyl group having 4 to 20 carbon atoms). 1. A stabilized polyolefin resin composition containing 0.5 to 15 (weight ratio) of Pionate). 2) The stabilized polyolefin resin composition according to claim 1, wherein the polyolefin resin is polypropylene. (3) Pentaerythritol-tetrakis (β-alkylthiopropionate) is
The stabilized polyolefin resin composition according to claims 1 and 2, which is tetrakis (β-dodecylthiopropionate).